The term C-076 is used to describe a series of compounds isolated from the fermentation broth of a C-076 producting strain of Streptomyces avermitilis. The morphological characteristics of the culture are completely described in copending U.S. Patent Application Ser. No. 772,601. The C-076 compounds are a series of macrolide with hydroxy substituents capable of being substituted with hydrocarbon substituents. Some of the C-076 compounds have more then one hydroxy group which may be so substituted, and procedures have been developed for the selective substitution at the various positions. The hydrocarbon substituted compounds thus produced have profound anthelmintic, insecticidal, ectoparasiticidal and acaricidal activity.